Slice your kohlrabi into 1cm (0.5 inch) large cubes. Place them in a large bowl, filled with water to prevent oxidation. Optionally you can add a wedge of lemon.
Pour the distilled white vinegar and water into a pot. Add the peppercorns, salt, sugar and coriander seeds. Bring to a boil, then remove from the heat. Strain the kohlrabi through a sieve and place tightly together into a glass .canning jar. Pour the vinegar mixture over it and cover with sterilized lids.
Cook in the oven
Preheat the oven to 80°C / 175 °F. Pour about 5 cm of water into a deep baking dish. Wrap a wet kitchen cloth around the glass jar, place the jar into the water. Cook for about 20 minutes in the oven, so that the kohlrabi cooks a bit. Remove the baking dish from the oven and let it cool in the water slowly.
Store your pickled kohlrabi in a dark room ( 8 - 10 °C / 45 - 50 °F ) for up to three years. It's the best served after 2 - 3 months.